Publication Date

2026

Presentation Length

Poster/Gallery presentation

College

Thomas F. Frist, Jr. College of Medicine

Department

Public Health, Department of

Faculty Mentor

Ryan Snowden, MD.

Presentation Type

Poster

Summary

Abstract:

Background:

Malnutrition is a significant risk factor for patients undergoing surgery, including those receiving spine surgery. These patients are at greater risk of adverse postoperative outcomes, impaired wound healing, and spinal fusion failure. Therefore, it is essential to identify at-risk, malnourished patients prior to intervention to mitigate any complications such as surgical site infections, unplanned readmissions, and reoperations. The primary focus of this study was to assess the accuracy of the Nestlé Mini Nutritional Assessment® (MNA®) on identifying true malnutrition amongst those patients undergoing spine surgery.

Methods:

We conducted a retrospective cohort study of 674 consecutive adults undergoing elective spine surgery. The primary outcome was biochemical malnutrition defined as serum prealbumin <  20 mg/dL, and the primary exposure was a binary preoperative nutrition screen categorized as positive (At Risk or Malnourished) or negative (Within Normal Limits). Preoperative covariates selected a priori included age, BMI, total instrumented levels, preoperative hemoglobin, ASA class, diabetes, and smoking status. Missing data were addressed using multiple imputation by chained equations (MICE; 20 imputations, fixed seed, 10-iteration burn-in), with results pooled using Rubin's rules. The association between the nutrition screen and biochemical malnutrition was estimated using unpenalized logistic regression with ASA class treatment-coded to a fixed reference. Multiplicative interaction terms between the screen and each covariate were tested in separate models. Screening performance was characterized by sensitivity, specificity, PPV, and NPV against the prealbumin reference, with exact 95% confidence intervals for sensitivity and specificity computed using the Clopper-Pearson method.

Results:

Among the study cohort, biochemical malnutrition, defined as a preoperative serum pre-albumin level <  20 mg/dL, was identified in 64 patients. Patients with biochemical malnutrition had significantly lower preoperative hemoglobin levels compared with well-nourished patients (12.42 ± 1.39 vs 13.62 ± 1.59 g/dL, p < 0.001). Higher American Society of Anesthesiologists (ASA) classification was also more common among malnourished patients (p < 0.001), with ASA class IV occurring more frequently in this group. The MNA® demonstrated a sensitivity of 42.2% (95% CI 30.9–54.4) and a specificity of 74.4% (95% CI 70.8–77.7). Additionally, the positive predictive value (PPV) was 14.8% (95% CI 10.3–20.6), while the negative predictive value (NPV) was 92.4% (95% CI 89.8–94.5).

Conclusion

Although the MNA® screening demonstrated limited sensitivity, a high NPV indicates its effectiveness in clinically ruling out malnutrition. Furthermore, accurate filtering of malnourished patients showed no significant differences amongst surgical variables, indicating that malnourishment was an independent factor that reflected the underlying biological composition of the patients. These findings suggest that the use of the MNA® in conjunction with preoperative hemoglobin and ASA classification should be done for accurate preoperative nutritional analysis in spinal surgery candidates.

Clinical Relevance:

The application of nutritional screening tools (MNA®) prior to major surgery will lead to enhanced screening efforts, greater determination of risk factors, and improved clinical decision-making.

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